CVE-2026-54740

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Source
https://cve.org/CVERecord?id=CVE-2026-54740
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54740.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-54740
Aliases
  • GHSA-xmpx-2j2f-c7g7
Published
2026-08-19T20:14:29Z
Modified
2026-10-28T02:30:43Z
Severity
  • 6.5 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N CVSS Calculator
Summary
Lemmy: Lower-ranked federated moderator can remove higher-ranked moderators
Details

Lemmy is a link aggregator and forum for the fediverse. Prior to 0.19.19 and 1.0.0-alpha.18, a lower-ranked remote moderator can remove a higher-ranked moderator by sending a signed ActivityPub Remove activity to the target instance. The local API uses LocalUser::is_higher_mod_or_admin_check to enforce moderator rank, but CollectionRemove::verify in crates/apub/activities/src/community/collection_remove.rs only calls verify_mod_action. CollectionRemove::receive dereferences self.object as an ApubPerson, creates a CommunityModeratorForm, and calls CommunityActions::leave without checking that the actor outranks the moderator identified by the object field. In communities with federated moderators, a junior moderator can therefore strip senior moderators from the community moderator list even though the local API rejects the same action. This issue is fixed in versions 0.19.19 and 1.0.0-alpha.18.

Database specific 
{
    "cna_assigner":  "GitHub_M",
    "cwe_ids":  [
        "CWE-862"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54740.json"
}
References

Affected packages

Git / github.com/lemmynet/lemmy

Affected ranges

Type
GIT
Repo
https://github.com/lemmynet/lemmy
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
f6e986e7e54d456aa1ffec38f1576c5bb15e0afd
Introduced
1edc9f922debc2c5b1aaaf29c495d7d4fe711b94
Fixed
0ab1cd744b659d0f5e35b77dbded142bed550487
Fixed
d127e714a66f34f6b9c8ea15f20097ac907cdf28
Fixed
ede1d348344ca2027fd1bc6a0cab25575c0c3a4c
Database specific
Show details 
{
    "extracted_events":  [
        {
            "range":  [
                {
                    "introduced":  "0"
                },
                {
                    "fixed":  "0.19.19"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StringRangeExpression"
        },
        {
            "range":  [
                {
                    "introduced":  "1.0.0-alpha.0"
                },
                {
                    "fixed":  "1.0.0-alpha.18"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StringRangeExpression"
        },
        {
            "range":  [
                {
                    "fixed":  "d127e714a66f34f6b9c8ea15f20097ac907cdf28"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        },
        {
            "range":  [
                {
                    "fixed":  "ede1d348344ca2027fd1bc6a0cab25575c0c3a4c"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        },
        {
            "original_tag":  "0.19.19",
            "range":  [
                {
                    "fixed":  "f6e986e7e54d456aa1ffec38f1576c5bb15e0afd"
                }
            ],
            "source":  "REFERENCES_TAG"
        },
        {
            "original_tag":  "1.0.0-alpha.18",
            "range":  [
                {
                    "fixed":  "0ab1cd744b659d0f5e35b77dbded142bed550487"
                }
            ],
            "source":  "REFERENCES_TAG"
        }
    ]
}

Affected versions

0.*
0.10.0
0.10.0-rc.12
0.10.0-rc.13
0.10.0-rc.7
0.10.1
0.10.2
0.11.0
0.11.0-rc.1
0.11.1
0.11.2
0.11.3-rc.4
0.11.4-rc.16
0.12.0
0.12.0-rc.1
0.12.0-rc.2
0.13.0
0.13.0-rc.1
0.13.5-rc.7
0.13.6-rc.2
0.14.0
0.14.0-rc.1
0.14.0-rc.2
0.14.1
0.14.2
0.14.2-rc.1
0.14.3
0.15.0
0.15.0-rc.7
0.15.1
0.16.0
0.16.0-rc.1
0.16.0-rc.2
0.16.0-rc.3
0.16.0-rc.4
0.16.1
0.16.1-rc.1
0.16.2
0.16.2-rc.1
0.16.2-rc.2
0.16.2-rc.3
0.16.3
0.16.3-rc.1
0.16.5
0.17.0
0.17.0-rc.1
0.17.0-rc.3
0.17.0-rc.4
0.17.1
0.18.0
0.18.0-rc.1
0.18.0-rc.2
0.18.0-rc.3
0.18.0-rc.4
0.18.0-rc.5
0.18.0-rc.6
0.18.0-rc.8
0.18.1
0.18.1-rc.1
0.18.1-rc.10
0.18.1-rc.4
0.18.1-rc.9
0.18.4-beta.7
0.19.0
0.19.0-beta.7
0.19.0-rc.1
0.19.0-rc.10
0.19.0-rc.11
0.19.0-rc.12
0.19.0-rc.13
0.19.0-rc.14
0.19.0-rc.15
0.19.0-rc.16
0.19.0-rc.2
0.19.0-rc.3
0.19.0-rc.4
0.19.0-rc.5
0.19.0-rc.6
0.19.0-rc.7
0.19.0-rc.8
0.19.1-rc.1
0.19.1-rc.2
0.19.10
0.19.10-beta.0
0.19.10-beta.1
0.19.10-beta.2
0.19.11
0.19.11-beta.0
0.19.11-beta.1
0.19.11-beta.2
0.19.12
0.19.12-beta.0
0.19.12-beta.1
0.19.12-beta.10
0.19.12-beta.11
0.19.12-beta.12
0.19.12-beta.2
0.19.12-beta.3
0.19.12-beta.4
0.19.12-beta.5
0.19.12-beta.6
0.19.12-beta.7
0.19.12-beta.8
0.19.12-beta.9
0.19.13
0.19.13-beta.1
0.19.14
0.19.14-beta.0
0.19.14-beta.1
0.19.14-beta.2
0.19.15
0.19.15-beta.0
0.19.16
0.19.16-beta.0
0.19.16-beta.1
0.19.17
0.19.17-beta.0
0.19.18
0.19.18-beta.0
0.19.18-beta.1
0.19.18-beta.3
0.19.2
0.19.2-rc.1
0.19.2-rc.2
0.19.2-rc.4
0.19.2-rc.5
0.19.3
0.19.3-rc.1
0.19.4
0.19.4-beta.1
0.19.4-beta.3
0.19.4-beta.4
0.19.4-beta.5
0.19.4-beta.6
0.19.4-beta.7
0.19.4-beta.8
0.19.4-rc.1
0.19.4-rc.10
0.19.4-rc.11
0.19.4-rc.2
0.19.4-rc.3
0.19.4-rc.4
0.19.4-rc.5
0.19.4-rc.6
0.19.4-rc.7
0.19.4-rc.8
0.19.4-rc.9
0.19.5
0.19.5-alpha.1
0.19.5-alpha.2
0.19.5-alpha.3
0.19.6
0.19.6-beta.14
0.19.6-beta.15
0.19.6-beta.8
0.19.6-beta.9
0.19.7
0.19.7-beta.1
0.19.7-beta.2
0.19.8
0.19.8-beta.0
0.19.9
0.19.9-beta.0
0.19.9-beta.1
0.19.9-beta.2
0.19.9-beta.3
0.19.9-beta.4
0.9.0
0.9.1
0.9.2
0.9.3
0.9.4
0.9.5
0.9.6
0.9.7
0.9.8
0.9.9
1.*
1.0.0-alpha.0
1.0.0-alpha.1
1.0.0-alpha.10
1.0.0-alpha.12
1.0.0-alpha.2
1.0.0-alpha.3
1.0.0-alpha.4
1.0.0-alpha.5
1.0.0-alpha.6
1.0.0-alpha.7
1.0.0-alpha.9
v0.*
v0.0.7.4
v0.0.8.1
v0.0.8.2
v0.0.8.3
v0.4.0.3
v0.5.10
v0.7.17
v0.7.18
v0.7.19
v0.7.20
v0.7.21
v0.7.22
v0.7.23
v0.7.24
v0.7.25
v0.7.26
v0.7.28
v0.7.29
v0.7.3
v0.7.30
v0.7.31
v0.7.32
v0.7.33
v0.7.34
v0.7.35
v0.7.36
v0.7.37
v0.7.38
v0.7.39
v0.7.4
v0.7.40
v0.7.41
v0.7.42
v0.7.43
v0.7.44
v0.7.46
v0.7.47
v0.7.48
v0.7.49
v0.7.5
v0.7.50
v0.7.52
v0.7.53
v0.7.54
v0.7.55
v0.7.56
v0.7.57
v0.7.59
v0.7.6
v0.7.61
v0.7.62
v0.7.63
v0.7.64
v0.7.7
v0.7.8
v0.8.0
v0.8.1
v0.8.10
v0.8.3
v0.8.5
v0.8.6
v0.8.7
v0.8.8
v0.8.9

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54740.json"